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Magazine articles
Anhydrous ammonia storage vessels in the pulp and paper industry, TAPPI JOURNAL, April 1997, Vol. 80(4)
Anhydrous ammonia storage vessels in the pulp and paper industry, TAPPI JOURNAL, April 1997, Vol. 80(4)
Magazine articles
1995 pulping conference succees with opportunities to participate, TAPPI JOURNAL, May 1996, Vol. 79(5)
1995 pulping conference succees with opportunities to participate, TAPPI JOURNAL, May 1996, Vol. 79(5)
Magazine articles
Ozone wasn't the whole story at the 1994 international pulp bleaching conference, TAPPI JOURNAL, November 1994, Vol. 77(11)
Ozone wasn't the whole story at the 1994 international pulp bleaching conference, TAPPI JOURNAL, November 1994, Vol. 77(11)
Journal articles
Magazine articles
Effect of high sulfate content on viscosity of recovery boiler molten smelt, TAPPI Journal March 2024
ABSTRACT: A systematic study was conducted to examine the effect of high sulfate content on the freezing temperature of molten smelt and how this may contribute to the formation of viscous jellyroll smelt in recovery boilers. The results show that even for recovery boilers with a smelt reduction as low as 70%, the sulfate content in smelt has no or little effect on smelt freezing temperature, and hence, on molten smelt fluidity. The perceived adverse effect of high sulfate content on smelt fluidity and on jellyroll smelt formation comes from the high sulfate content in deposits that have fallen from the upper furnace. Fallen deposits may or may not form jellyroll smelt, depending on whether or not they can melt and be well-mixed with molten smelt by the time they reach the smelt spouts. It is not the high sulfate content in smelt resulting from the low smelt reduction efficiency that makes molten smelt viscous and forms jellyroll smelt, but rather, it is the incomplete melting of fallen deposits that results in one of the proposed mechanisms for jellyroll smelt formation.
Magazine articles
Measuring customer perception of print quality, TAPPI JOURNAL, March 1990, Vol. 73(3)
Measuring customer perception of print quality, TAPPI JOURNAL, March 1990, Vol. 73(3)
Magazine articles
Hydrogen peroxide: innovations in chemical pulp bleaching, TAPPI JOURNAL, January 1991, Vol. 74(1)
Hydrogen peroxide: innovations in chemical pulp bleaching, TAPPI JOURNAL, January 1991, Vol. 74(1)
Magazine articles
Influence of tube metallurgy on corrosion resistance of liquor heaters, TAPPI JOURNAL, March 1991, Vol. 74(3)
Influence of tube metallurgy on corrosion resistance of liquor heaters, TAPPI JOURNAL, March 1991, Vol. 74(3)
Magazine articles
Nonchlorine bleaching conference: the future is here, TAPPI JOURNAL, July 1992, Vol. 75(7)
Nonchlorine bleaching conference: the future is here, TAPPI JOURNAL, July 1992, Vol. 75(7)
Journal articles
Magazine articles
Black liquor evaporator upgrades— life cycle cost analysis, TAPPI Journal March 2021
ABSTRACT: Black liquor evaporation is generally the most energy intensive unit operation in a pulp and paper manufacturing facility. The black liquor evaporators can represent a third or more of the total mill steam usage, followed by the paper machine and digester. Evaporator steam economy is defined as the unit mass of steam required to evaporate a unit mass of water from black liquor (i.e., lb/lb or kg/kg.) The economy is determined by the number of effects in an evaporator train and the system configuration. Older systems use four to six effects, most of which are the long tube vertical rising film type. Newer systems may be designed with seven or even eight effects using falling film and forced circulation crystallization technology for high product solids. The median age of all North American evaporator systems is 44 years. Roughly 25% of the current North American operating systems are 54 years or older. Older systems require more periodic maintenance and have a higher risk of unplanned downtime. Also, older systems have chronic issues with persistent liquor and vapor leaks, shell wall thinning, corrosion, and plugged tubes. Often these issues worsen to the point of requiring rebuild or replacement. When considering the age, technology, and lower efficiency of older systems, a major rebuild or new system may be warranted. The intent of this paper is to review the current state of black liquor evaporator systems in North America and present a basic method for determining whether a major rebuild or new installation is warrant-ed using total life cycle cost analysis (LCCA).
Journal articles
Magazine articles
A feasibility study of using the organic Rankine cycle for power generation from the flue gases of recovery boilers, TAPPI Journal August 2022
ABSTRACT: Almost 415 tons/h of flue gases with a temperature of 160°C are released to the atmosphere from the recovery boiler of a pulp mill with capacity of 1000 air dried (a.d.) metric tons of pulp per day. This is a large waste heat stream that can be used to generate power, to decrease the operating costs of a pulp mill, and to save carbon dioxide (CO2) emissions. In this work, the feasibility of using an organic Rankine cycle (ORC) with ammonia as the working fluid to generate power from the flue gases of recovery boilers is studied. CHEMCAD and Taguchi methods are used for simulation of the process and for optimization of operating conditions, respectively. The temperature of the ammonia and flue gases at the exit of evaporator, exit pressure of the pump and turbine, and the degree of subcooling of ammonia at the exit of the condenser are five operating parameters that are manipulated to optimize the process. Three different scenarios are defined: minimizing the net power cost, maximizing the ORC efficiency, and maximizing the net profit. Different aspects of these scenarios, such as net power generation, cost, efficiency, and CO2 emission savings are discussed, and optimum operating conditions are reported.